In one of my previous blog posts on human social brain evolution, I already briefly mentioned the concept of attachment and attachment style. Here, I would like to elaborate on these considerations by describing in more detail what we have learned about the neural mechanisms underlying attachment behaviors in humans, and how such information could help us maintain better relationships with others.

In the late 1960s and early 1970s, Mary Ainsworth and John Bowlby first described a developmental psychological framework related to social interactions that has since become known as attachment theory. It states that, in order to survive, infants form a strong bond to their primary caregiver(s); they become attached. As infants grow older, this attachment evolves from a primarily biologically driven “survival instinct” into a sophisticated “cognitive-emotional social relationship processor.” A person’s mode of attachment, also called attachment style, determines what he/she will expect from social interactions, and how she/he will use cognitive and emotional resources for self-regulation during times of social emotional stress.

Central to the understanding of the concept of attachment is the assumption that all infants will become attached, but that such attachment can be either secure (i.e., “good”) or insecure (i.e., “bad”). It all depends on how the primary caregiver(s) respond to the infant’s attempts to establish a close social connection. Ideally, the caregiver(s) are available, responsive and caring in times of need. Infants consequently learn to trust in others and their own social emotional abilities; they can establish a secure attachment style. Unfortunately, such scenario does not always happen, allowing for the formation of an insecure attachment style in infants. If the primary caregiver(s) react in an unpredictable or inconsistent manner to the infant’s social approach signals, an anxious attachment style is bound to emerge. The latter is characterized by a constant fear of abandonment and need for reconfirmation due to a very low self-esteem. In turn, if the primary caregiver(s) is/are unavailable or unresponsive in times of need, infants will develop an avoidant attachment style. They learn to expect social rejection and fail to associate social interactions with positive experiences. Interacting with others may even be seen as futile or dangerous. Consequences are social-emotional closure and the denial for the need of social relationships. Some more information can also be found in blogs by Lisa Firestone (for example here).

Although the foundations of a person’s (secure versus insecure) attachment style are laid early in life, this process can have a strong influence on social emotional abilities and well-being throughout the lifespan, and even affect future generations. This comes from the fact that an individual’s attachment style is thought to remain rather stable from childhood to adolescence and adulthood, and may be transmitted from one generation to the next. Given that at least one third of people are believed to have an insecure attachment style and attachment insecurity is a known risk factor for the emergence of psychopathology (e.g., social anxiety disorder, or borderline personality disorder), attachment insecurity has a high potential for causing considerable problems in society.

In order to develop new detection, prevention and intervention strategies for social emotional difficulties associated with attachment insecurity, researchers have recently begun to investigate the neural basis of attachment style in humans. The main goal of such approach is to find neural markers of attachment insecurity in the human brain, allowing for understanding what may cause people to react with avoidance or anxiety to social emotional signals. Because it is easiest to establish such brain-behavior associations in adults, initial research has focused on adult populations.

Let’s first consider attachment anxiety. Converging evidence from adults suggest that this insecure attachment style is characterized by hyper-sensitivity to social emotional information in general, particularly so if negative. Anxiously attached individuals show high activity in brain areas that normally process social rejection and conflict, as well as maintain high arousal and negative emotionality. It looks as if anxiously attached people’s brains are constantly in a high alert state, monitoring the environment for potential signs of social emotional threats. Even if there are none.

Attachment avoidance, in turn, seems to considerably lower the brain’s responsiveness to social emotional information, especially so if positive. Avoidantly attached individuals show low activity in brain areas that usually process reward and prosocial motivation. This even appears to hold true for mothers seeing pictures of their own smiling infants, normally representing very potent inducers of reward-related social brain activity. It appears as if avoidantly attached individuals do not feel good when interacting with others. Even if these interactions are mutual.

Although admittedly reductionist (see here for more details), the above simplified description of the neural basis of attachment anxiety and avoidance nicely illustrates the strong influence the environment within which a person grows up in can have on social emotional brain responses during adulthood. These findings in humans furthermore nicely accord with data from animal studies (see here and here), the latter suggesting that such environmental effects can even override potential genetic predispositions for attachment insecurity.

The practical implications of the above-mentioned brain activations associated with attachment anxiety and avoidance are manifold. Firstly, we should be strongly aware of the fact that our behavior towards infants (as well as children and adolescents) can crucially influence their social emotional brain development, shaping how they themselves will behave during adulthood. Key elements of such awareness should be the maintenance of a stable, predictable and responsive environment within which children grow up in. Second, and associated with the first point, we should be more aware of our own attachment style to better understand our own reactions in the course of social interactions. This can help us to proactively change our social emotional behavior, or at least disengage from interactions early enough to prevent damage. And third, knowing more about the brain basis of attachment anxiety and avoidance, we can start developing new prevention and intervention strategies specifically targeting affected social emotional reward and threat behaviors and underlying brain circuits.

Ongoing research on the neural basis of attachment insecurity in adolescents and children will hopefully soon add more information, allowing for an early detection and prevention of, and/or intervention in the case of social emotional problems associated with attachment insecurity. The sooner we can act, the better.